Question

A cationic colloidal electrolyte forms micelle at ${10}^{-4}$ M concentration in water. If $1$ mm${}^3$ solution contains ${10}^{12}$ micelle structures, then the number of cations involved in one micelle is _______.

Note: Write the nearest integer.

Answer 1

$1L$ corresponds to ${10}^{-4}$ moles which also corresponds to ${10}^{6}m{m}^3$.

Hence, $1m{m}^3$ contains $\frac{{10}^{-4}}{{10}^6}={10}^{-10}$ moles.

But this corresponds to ${10}^{12}$ micelles.

Thus, $1$ micelle corresponds to ${10}^{-22}$ moles.

This is equal to ${10}^{-22}\times 6.0\times {10}^{23}=60$ cations.

Hence, the number of cations involved in $1$ micelle is $60$.